Steve has a great post on measuring the chatter using Ice Rocket and other tools. I'm a big fan of Ice Rocket and like Steve tend to use this more than Blogpulse. With tools like these there is no excuse for PR not to start speaking to the conversation in its dashboard.
Our challenge as communicators is to now move to understand the impact of these conversations on purchasing and other customer behaviors. Then we go from speaking about the conversation in the context of communications to demonstrating the value of conversations to the business.